This invention relates to certain diphenylaliphatic borane imidazole complexes and derivatives thereof. In a further aspect, the invention relates to the use of such complexes as agricultural fungicides.
A large amount of crop loss and plant damage is incurred each year due to plant diseases caused by four classes of fungi: Ascomycetes, causing a large number of leaf spots, blights, soil-bourn and post-harvest diseases; Deuteromycetes, also causing a large number of leaf spots, blights, soil-bourn and post-harvest diseases; Basidiomycetes, causing rust, smuts, bunts and soil borne-diseases; and Phycomycetes, causing downy mildews, leaf blights and soil-bourn diseases.
Leaf spot and blight diseases, such as those induced by species of Leptosphaeria, Mycosphaerella, Alternaria, and Helminthosporium cause damage to many crops such as maize, wheat, banana, and solanaceous crops and are difficult to control.
Various species of the genus Botrytis are responsible for diseases causing large losses in numerous vegetable, ornamental and vine crops. Present fungicides such as benzimidazoles and dicarboximides cannot adequately control these diseases due to the development of resistance by the pathogen.
The late blights and downy mildew plant diseases produced, for example, by Phytophthora and Plasmopara are very destructive to grape and solanaceous crops, e.g., potato, tomato. These diseases are also difficult to control due to the development of resistance to the leading systemic fungicides used to control these diseases.
Thus, it would be desirable to develop new fungicides which are effective to control plant diseases and especially in the case of late blights, mildew and Botrytis-produced diseases which are not subject to cross-resistance of the pathogen and which do not cause significant injury to the plants (i.e., are relatively non-phytotoxic).
U.S. Pat. No. 3,062,708 generally teaches that amine complexes of triphenylborane with certain Lewis bases have antifungal activity. The patent shows in vitro activity with respect to triphenylborane-imidazole and illustrates in vivo activity against tomato early blight, bean rust, late blight and seed rot (Pythium ultimum) with respect to certain triphenylborane amines including complexes with piperidine, pyridine and 4-ethylpyridine.
U.S. Pat, No. 3,211,679 teaches that triarylborane amine complexes with pyridine or a variety of substituted pyridines are useful as toxicants for antifouling paint and that such paints import residual toxicity to marine borers to wood structures.
U.S. Pat. No. 3,686,398 teaches that certain 10,9-boroxarophenanthrenes are useful to control fungi and exhibited preventative control of bean rust and celery late blight.
U.S. Pat. No. 3,696,103 teaches that certain di(substituted and unsubstituted phenyl)azaborolidines exhibit fungicidal, insecticidal, acaricidal and herbicidal activity The fungicidal activity is described as polyvalent and is shown against bean anthracnose (Collectrotrichum lindemythianum), tomato mildew (late blight) (Phytophthora infestans), tobacco mildew (blue mold) (Peronospora tabaci), cucumber (powdery) mildew (Erysiphe cichoracearum) and wheat rust (Puccinia glumarum) at quantities of between 10 and 200 g of active substance per hectoliter of liquid diluent such as water.
U.S. Pat. No. 4,613,373 teaches that certain tetra(substituted and unsubstituted phenyl) boranes complexed with a heterocyclic amine are useful as antifouling, antiseptic, and antifungal agents in many industrial applications. In vitro inhibiting activity of certain of patentees compounds against certain fungi are shown in Table 4 of the patent.
Based on the Derwent Abstract, Japanese Patent Application Publication 62-277307 describes complexes of tri(substituted phenyl)borane with amines and nitrogen containing heterocycles as useful as insecticides, miticides and nematocides. Based on Derwent Abstract 5188957, Japanese Patent Application publication JP 1056684 published Mar. 3, 1989 discloses certain tetraphenylboron-onium complexes useful as agricultural and industrial fungicides.